<template>
    <div>
        <p>请选择你要购买的书籍</p>
        <ul>
            <li v-for="(item, ind) in arr" :key="item.id" @click="addFn(ind)">{{ item.name }} <button>买书</button></li>
        </ul>
        <table border="1" width="500" cellspacing="0">
            <tr>
                <th>序号</th>
                <th>书名</th>
                <th>单价</th>
                <th>数量</th>
                <th>合计</th>
            </tr>
            <tr v-for="(item, index) in arr" :key="item.id">
                <th>{{ index + 1 }}</th>
                <th>{{ item.name }}</th>
                <th>{{ item.price }}</th>
                <th>{{ item.count }}</th>
                <th>{{ item.price * item.count }}</th>
            </tr>
        </table>
        <p>总价格为:{{ allPrice }}</p>
    </div>
</template>

<script>
export default {
    data() {
        return {
            arr: [
                {
                    name: '水浒传',
                    price: 107,
                    count: 0,
                },
                {
                    name: '西游记',
                    price: 192,
                    count: 0,
                },
                {
                    name: '三国演义',
                    price: 219,
                    count: 0,
                },
                {
                    name: '红楼梦',
                    price: 178,
                    count: 0,
                },
            ],
        }
    },
    methods: {
        addFn(i) {
            this.arr[i].count += 1
        },
    },
    computed: {
        allPrice() {
            return this.arr.reduce((sum, item) => (sum += item.price * item.count), 0)
        },
    },
}
</script>
